The present invention relates to the field of processing compressible material such as scrap material, and more particularly, relates to an apparatus which forms bales of compressible material and subsequently straps the bale.
The use of baling apparatus is common in many industries to reduce a compressible material to compact bales for easy handling and storage. For example, balers can be used to bale virgin materials, solid waste, paper, aluminum cans and plastic to name a few applications. Large capacity baling apparatus capable of producing relatively large, high-density bales, are usually either of two types, vertical or horizontal. Vertical baling equipment employs a compression chamber through which a vertically moving ram or compression head is translated. Horizontal balers employ a horizontally moving compression ram. Certain balers in the prior art also employ an ejector ram which is transverse to the compression ram and ejects the bale when completed. It is this later type of baler to which the invention is directed.
Horizontal balers in the prior art are basically made of a hollow longitudinal body having a baling chamber, having dimensions approximately those of the finished bale, at one end thereof, and an elongated, open end, horizontal chamber into which the scrap material is introduced. A main ram is provided so as to reciprocate inside the hollow body to push the compressible material into the baling chamber. In many of these prior art balers, the main ram could extend only to the edge of the baling chamber. Balers of this type have the disadvantage that full compression of the material supplied does not occur until the baling chamber is completely filled and more material is forced into the chamber by the ram. To provide additional material the ram is pulled back from the baling chamber so as to allow additional material to fall into the baler.
As a result of the ram only extending to the edge of the baling chamber, and retracting to fully expose the inlet opening after each compression so as to allow a random quantity of material to be supplied, the balers in the prior art could not make bales of a uniform given density. Additionally, this prevented balers from achieving a high density bale. For example, for aluminum cans a density of 20-25 lb/ft.sup.3 was the maximum attainable.
In some balers of the prior art, strapping means are provided so as to strap the completed bale as it is forced from the baler by the ejector ram. Various types of strapping devices are currently known in the art. However, many share the problem of not providing a simple means for indexing where the straps should be located on the bale. Many older devices can only locate the straps at fixed, predetermined locations, thereby not allowing for different strap configurations for different types of materials. Other devices in the art allow for indexing of strap location by use of a plurality of dogs located along the cylinder, which trigger a limit switch which causes a strap to form around the bale. The spacing of the straps is accomplished by physically moving the dogs to new locations. This has proved to be a difficult and time consuming task which results in a strapping means with less than ideal flexibility for various configurations of strap.